The overall goal of this project is to contribute to the understanding of the neural basis for memory and language. The two topics are combined in this project because the aspects of memory and language we propose to investigate are closely related theoretically and experimentally. The experimental approaches uses the lesion method to interrelate neuropsychological and neuroanatomical findings. The principal aim is to define further the neural basis for the retrieval of concepts and words, in regard to different domains of knowledge, while addressing important issues of interpretation and method. The proposed experiments were planned to answer three main questions: (1) Are the systems underlying the retrieval of concepts neuroanatomically separable from those underlying the retrieval of the corresponding worlds? (2) Are the neural systems required to retrieve knowledge for different conceptual categories (actions, spatial relationships, concrete entities, abstractions) partially segregated, and if so, does the segregation obtain for both concepts and words? (3) What is the influence of various factors related to the stimuli, subjects, and experimental tasks, on the retrieval of concepts and words? By testing specific hypotheses associated with each of these questions, we hope to identify systematic relationships between multi-component neural systems and different domains and processing levels, and to identify cognitive and neural factors which underlie those relationships. Our approach capitalizes on the unique opportunities afforded by the modern investigation of focal lesions in humans. The results will contribute to a more precise formulation of the neural basis of memory and language, at systems levels, and to specification of the neural and cognitive architectures pertaining to representation and access of concepts and words. The results will complement those obtained with other approaches (functional imaging, electrophysiology), shed light on the diagnosis and physiopathology of the amnesias and aphasias, and assist in the development of programs to rehabilitated the large numbers of neurological patients with conditions such as stroke, head injury, and Alzheimer's disease, who develop memory and language impairments.